Aquatic Biologist: Aquatic ecologist Studies plants and animals living in water, and environmental conditions affecting them: Investigates salinity, temperature, acidity, light, oxygen content, and other physical conditions of water to determine their relationship to aquatic life. Examines various types of water life, for example plankton, worms, clams, mussels, and snails. May also specialize in study of salt water aquatic life and be designated Marine Biologist (professional industry), or fresh water aquatic life and be designated Limnologist (professional industry). May also specialize in culture, breeding, and raising of aquatic life, for example shrimp, lobsters, clams, oysters, or fish, and commercial fish farm operations and be designated Aquaculturist (professional industry).